Maybe THEY did, but it started again a few days ago, maybe a week ago? A few days ago, I started being able to still see activities, but seeing zeroes for sleep, steps, intensity minutes, floors climbed,
You need to (sucessfully) sync your watch with Garmin Connect for beign able to see it there. If you annot, or you did, there are basically three possibilities:
When the synchronisation works (the white sync circle closes and turns green), but not all the data is appearing in your account, then it very probably means that your device is associated with multiple accounts, and a part of the data lands in the other account. It frequently happens for example when you reinstall the application, and inadvertently sign up a new account instead of signing into the original one. Follow the instructions from the support document Data is Missing from My Garmin Account After Syncing to resolve the issue.